Habitat loss and gain : influence on habitat attractiveness for estuarine fish communities
Amorim, Eva; Ramos, Sandra (Biologist); Elliott, M. (Michael), 1952 November 3-; Franco, Anita; Bordalo, Adriano A.
Institute of Estuarine and Coastal Studies; Institute of Estuarine and Coastal Studies; Institute of Estuarine and Coastal Studies; Institute of Estuarine and Coastal Studies
Estuaries; Habitat changes; Fish habitat attractiveness; Physiotopes
Habitat structure and complexity influence the structuring and functioning of fish communities. Habitat changes are one of the main pressures affecting estuarine systems worldwide, yet the degree and rate of change and its impact on fish communities is still poorly understood. In order to quantify historical modifications in habitat structure, an ecohydrological classification system using physiotopes, i.e. units with homogenous abiotic characteristics, was developed for the lower Lima estuary (NW Portugal). Field data, aerial imagery, historical maps and interpolation methods were used to map input variables, including bathymetry, substratum (hard/soft), sediment composition, hydrodynamics (current velocity) and vegetation coverage. Physiotopes were then mapped for the years of 1933 and 2013 and the areas lost and gained over the 80 years were quantified. The implications of changes for the benthic and demersal fish communities using the lower estuary were estimated using the attractiveness to those communities of each physiotope, while considering the main estuarine habitat functions for fish, namely spawning, nursery, feeding and refuge areas and migratory routes. The lower estuary was highly affected due to urbanisation and development and, following a port/harbour expansion, its boundary moved seaward causing an increase in total area. Modifications led to the loss of most of its sandy and saltmarsh intertidal physiotopes, which were replaced by deeper subtidal physiotopes. The most attractive physiotopes for fish (defined as the way in which they supported the fish ecological features) decreased in area while less attractive ones increased, producing an overall lower attractiveness of the studied area in 2013 compared to 1933. The implications of habitat alterations for the fish using the estuary include potential changes in the nursery carrying capacity and the functioning of the fish community. The study also highlighted the poor knowledge of the impacts of habitat changes on fish due to coastal development and urbanisation and emphasises that ecosystem management and conservation will benefit from a wider understanding of habitat functional roles and habitat changes influencing the functioning and structure of the fish communities.
- The University of Hull
- Peer reviewed
- Journal title
- Estuarine, coastal and shelf science
- Publication date
- ISSN (Print)
- ISSN (Electronic)
- Full text not available in this repository until: August 2018
This is a description of an article which has been published in: Estuarine, coastal and shelf science, 2017
- Published article